Neutron scattering study of the field-induced tricritical point in MnSi

ORAL

Abstract

The intermetallic compound MnSi attracts great scientific interest due to two unusual phase transitions, namely the transition from the conical phase to a skyrmion lattice in small fields and the transition from the helical to the paramagnetic phase without external magnetic field that was recently identified to be a fluctuation induced first-order transition, i.e. a so called Brazovskii-transition. Recent measurements of the specific heat provide striking evidence for a tricritical point (TCP), were the first order transition alters to second order. We report neutron spin echo measurements using the MIEZE technique. The recorded quasi elastic linewidth shows a change of the characteristic spin fluctuations at the TCP. The combination with additional SANS measurements and a generalized Brazovskii theory establishes a consistent picture of the statics and dynamics of the transition.

*Financial support by ERC-AdG (291079 TOPFIT) and through DFG TRR80 is greatfully acknowledged.

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Authors

  • Jonas Kindervater

    • Physik-Department, Technische Universit\"at M\"unchen, Garching, Germany
    • Institute for Quantum Matter and Jonhs Hopkins University

  • A. Bauer

    • Physik-Department, Technische Universit\"at M\"unchen, Garching, Germany

  • M. Garst

    • Institute for Theoretical Physics, Universit\"at zu K\"oln, K\"oln, Germany

  • M. Janoschek

    • Los Alamos National Laboratory, Los Alamos, USA

  • N. Martin

    • Heinz Maier-Leibnitz Zentrum, Technische Universit\"at M\"unchen, Garching Germany

  • S. M\"uhlbauer

    • Heinz Maier-Leibnitz Zentrum, Technische Universit\"at M\"unchen, Garching Germany

  • W. H\"aussler

    • Heinz Maier-Leibnitz Zentrum, Technische Universit\"at M\"unchen, Garching Germany

  • P. B\"oni

    • Physik-Department, Technische Universit\"at M\"unchen, Garching, Germany

  • C. Pfleiderer

    • Physik-Department, Technische Universit\"at M\"unchen, Garching, Germany